html, body, #canvas {
  height: 100%;
  margin: 0;
  overflow: hidden;
}

h1 {
  position: fixed;
  z-index: 100;
  left: 10px;
  top: 10px;
  background: white;
  padding: 5px 10px;
  margin: 0;
  opacity: 0.7;
}

body.fail {
  background: red;
}

body.success {
  background: lightgreen;
}